Tenesmus: An Unusual Presentation of Delayed Prostate Adenocarcinoma Recurrence

We describe a case of prostate cancer recurrence 25 years after radical prostatectomy. Our patient is a 77-year-old male with past medical history pertinent for obesity and coronary artery disease. The patient's initial presentation in 1994 was for persistent lower urinary tract symptoms. He was subsequently diagnosed with high-grade prostate adenocarcinoma and underwent radical prostatectomy. The patient was followed up postoperatively for 16 years and deemed to be in clinical and biochemical remission with undetectable prostate-specific antigen (PSA). Twenty-five years post-operatively, the patient was evaluated with an investigatory colonoscopy for tenesmus, constipation, and change in stool caliber. Colonoscopy revealed significant anal canal stenosis. Biopsy of the lesion showed prostate adenocarcinoma recurrence. Prostate cancer recurrence presenting with only gastrointestinal symptoms is highly unusual, especially in a patient who never received radiotherapy and had been in remission for 25 years.